**Answer:**

ur mom

**Explanation:**

jk it's prb something like foxy

Here is some ranting.

You haven't specified programming language. And every type of loop runs only when a condition is true (that is the definition of a loop).

And here is the answer.

Well, there is [code]for[/code], [code]while[/code] and in some languages even [code]do while[/code].

Hope this helps.

**Answer:**

**B.O(n).**

**Explanation:**

Since the time complexity of visiting a node is O(1) in iterative implementation.So the time complexity of visiting every single node in binary tree is O(n).We can use level order traversal of a binary tree using a queue.Which can visit every node in O(n) time.Level order traversal do it in a single loop without doing any extra traversal.